Micromax A310 — battery problem

Address:

Kamrup Metropolitan, Assam

I purchased Micromax A310 on 6th November and from the very first day, I got battery problem. I charging my phone 100 % but when it discharging it's coming smoothly up to 70 or 60%.then suddenly it discharge 30 to 40 % within 2 or 3 minutes and reaches 30 or 40 %... Then it discharging smoothly again... I checked battery graph couple of times and always found there only a straight line... I already have Sony xperia z... But this time I preferred Micromax... I think I make a big mistake by choosing Micromax... Never I will advise my frnd to buy Micromax handset...